Process of producing artificial building stones, bricks, &amp;c.



No. 663,904. I Patented Dec. I8, 1901 P. KLEBER.

PROCESS OF PRODUCING ARTIFICIAL BUILDING STONES, BRICKS, 8L6.

(Application filed July 15, 1899.)

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Unrrn ATET Enron.

PROCESS OF PRODUCING ARTIFICIAL BUILDING STONES, BRICKS, &c.

SPECIFICATION forming part of Letters Patent No. 663,904, dated December8, 1 00- Application filed July 15,1899. Serial No. 723,924. (Nospecimens.)

To aZZ 1072,0117, it may concern:

Be it known that 1, PETER KLEBER, manufacturer, a subject of the Emperorof Germany, residing at 64 Trierer-Allesstrasse, Malatatt-Burbach, RhineProvince, in the Kingdom of Prussia, Germany, haveinvented a certain newand useful Process for the Production of Artificial Building Stones,Bricks, and Like Articles, (for which I have filed application forpatent in Great Britain, No. 1,573, dated January 23, 1899,) of whichthe following is a specification.

This invention relates to an improved process for the manufacture ofartificial building stones and brick from a mixture of sand and lime bywhich artificial stone or bricks are more quickly produced of a betterquality, at a lower cost, and by. less costly means than the processeshitherto employed in rendering mixtures of sand and lime into artificialstone or bricks.

The objects of the improved process are to avoid the use of an excessivequantity of water beyond the amount required for the complete hydrationof the lime used, so as to ren-,

der unnecessary the preliminary drying operation otherwise requisite; toeconomize fuel in the subsequent hardening process; to obtain a mixturewhich can be conveniently handled in the process of molding it bymechanical pressure and which will set to some extent before it isfinally hardened or indurated by the action of high-pressure steam, andto wholly avoid the use of the expensive and troublesome moldsfrequently used in other such processes within the steam-chambers inwhich the ind uration or hardening is effected. These objects areattained in the manner hereinafter described.

In carrying the invention into effect one part of ground burned lime ismixed with from eight to fifteen parts, by weight, of moist sand, thequantity of moisture present in the sand preferably being that which itnormally contains in its natural condition. and sand are uniformlyincorporated with each otherbybeingintimatelyand thoroughly mixed withina mixing-machine of any ordinary construction. During the operation ofmixing a portion of the lime is hydrated or slaked, accompanied by aconsiderable rise of temperature of the mass, and thus the The limewhole of the moisture originally present in the sand combines with aportion of the lime, so that when the operation of mixing [which should,preferably, be continued until the whole of such moisture has combinedwith the lime) is completed the resulting mixture is in a drypulverulent form, having a volume about twenty per cent. greater thanits original volume. By this means a mixture of even and uniformcomposition is obtained with the expenditure of a minimum amount ofpower. The mixture is then discharged from the first mixing-machine intothe inlet-hopper of a second mixing-machine. With some descriptions oflime it is found to be advantageous to allow the mixture to remain atrest in the hopper of the second mixing-machine before treating itfurther with the object of insuring that the whole of the moistureoriginally present in the sand shall enter into chemical combinationwith that portion of the lime Whichitis chemically equivalenttohydrating.

The treatment in the second mixing-machine consists in adding to the drypulverulent mixture by means of a sprinkler or other appropriate devicefor evenly distributing water in jets or sprays such a further quantityof water, and no more, as will sufiice to slake or hydrate the remainderof the lime which was not slaked or hydrated in the first stage of theprocess. The mixing is continued until the whole of the water added isuniformly and evenly distributed throughout the mass A considerable risein temperature, due to the hydration of the further quantity of lime,results, and if the operation is properly conducted and an excess ofwater beyond that chemically necessary for the hydration of the whole ofthe lime has not been added the resulting mixture is of a dry andpulverulent form. It is highly important that an excessof water shouldnot be used at this stage of the process; otherwise a sloppy mass willbe produced of uneven composition and the hydration of the lime will notbe so rapid as when an excess of water is absent. Moreover, the mixtureis effected with a less expenditure of power than would be requisite inthe case of the plastic mass which would be the result of adding anexcess of Water and a more thorough and intimate mixture, andconsequently more comcase.

plete hydration of the lime is obtained in a shorter time than wouldotherwise be the When the hydration of practically the whole of the limehas been effected, a small additional quantity of water or of milk oflime may be added in order to temper the whole into a more or lessplastic mass and render it into such a condition that it will coherewith a considerable degree of firmness when submitted to mechanicalpressure in the molds of the presses subsequently employed. The quantityof water or of milk of lime necessary for this operation will dependvery considerably upon the state of fineness of division of the sand andlime employed and more or less upon the other physical characteristicsof these materials. The object, however, to be fulfilled is theproduction by means of a minimum quantity of Water of 'a more or lessplastic mass which will firmly cohere when submitted to pressure inmechanical molding-presses and which will to a certain extent set or.harden after pressure and before it is hardened by the subsequentprocess of steaming. Great care must, however, be exercised to add nomore water than is absolutely necessary for this purpose, as any excessso added will have to be eventually evaporated out of the mass in thesteaming-chambers, and thus considerable delay and increased expense byreason of the fuel thus Wasted will be entailed, which it is one of thespecial objects of this invention to avoid.

The mass discharged from the second mixing-machine is conveyed anddistributed by means of a reciprocating channel-frame to a series ofhoppers superposed above the presses used for molding the mixture intobricks or other articles of the desired shape and size.

The accompanying drawing illustrates in diagrammatic longitudinalsection an arrangement of a reciprocating channel-frame otsuperposedabove the m olding-presses. The channel-frame a is supported by lateralpivoted arms I) and is inclined in the direction in which thelime-andsand mixture is distributed. The reciprocation is effected froma counter-shaft c bym eans of a crank or crankdisk d, mounted thereupon,and a connecting-rod e.

The mixture of sand and lime may be delivered upon the reciprocatingchannel-frame a by means of a conveyerj, which conveys the mixture froma lower floor, where the first mixing may take place.

In the movement of the reciprocating channel-frame a the mixture iscaused, by means of the reciprocation thereof, to pass along its entirelength, and in so doing a certain quantity of the mixture falls throughapertures g h, suitably provided therein, into the 110ppers g it, placedabove each of the moldingpresses 2'. Each of the apertures g h men-'tioned is capable of being closed and each of the hoppers g h, whichfeed the presses t, into which the mixture is delivered, is divided intotwo compartments 9 and h, so as to provide for alternate working.

It is found to be an advantage, in order to insure thorough and completehydration of the whole of the lime, to allow the mass to stand beforemolding it for a period of from ten to thirty-six hours after it hasbeen pre pared in the manner hereinbefore described, the exact timebeing determined by the condition and appearance of the mass. For thispurpose each of the compartments in each of the series of hoppers isfilled one day and allowed to remain over night for use in the presseson the following day, the other compartment of the hopper being used toreceive the mass intended to be used on the next day following, the sizeof the hoppers and the respective compartmentsbeingadjustedaccordingly.The mixture after standing, as above described, is then in its freshcondition fed into the presses, which may be of any usual construction,and is therein molded by mechanical pressure into bricks or otherarticles of the desired shape and size. The molded bricks or otherarticles are then piled or stacked upon trucks or carriages ofconvenient size and suitable construction and without any preliminarydrying process, such, as is used in other processes, and the loadedtrucks are conveyed to and placed in steaming-chambers of suitable sizeand construction,where they are subjected to the action of steam of apressure, preferably, of from six to eight atmospheres for a period offrom three to ten hours, according to circumstances. By the action ofthe steam calcium silicates are formed in the body of the molded mass,and as a consequence induration and hardening of the bricks or otherarticles result. The pressure of the steam or the duration of treatmentmay be varied or increased for the purpose of effecting more rapid or agreater degree of induration.

By the preparation and treatment of the mixture in the mannerhereinbefore described bricks or other articles so prepared from it canbe ind urated at a higher pressure of steam without undergoingdisintegration. There is also the further advantage that the moldsrequired to be used in other processes for holding the mixtures of sandand lime during induration, so as to avoid cracking or disintegration,are in this process quite unnecessary, and thus the use and maintenanceof such molds, which are both costly and cumbersome and expensive tomaintain and use, are altogether avoided.

To the mixture produced in the second mixin g-machine may be addedcement,slate-dust, or other substances of a like nature as bodymaterials or substances intended to impart any particular color to theindicated articles.

Having now described my invention, I desire it to be understood that Iam aware that artificial stone or bricks have been made by the processof treating a mixture of sand and lime with high-pressure steam. 1therefore IIO complete hydration, thirdly, bringing the mixture into aplastic cohesive condition by the addition of a minimum amount of Water,molding said plastic mixture into blocks, and finally subjecting suchblocks to the action of high pressure steam, substantially as described.

In Witness whereof I have hereunto set my hand in presence of twoWitnesses.

PETER KLEBER.

Witnesses:

HENRY HASPER, WOLDEMAR HAUPT.

